re: Low Band Verticals de N4KG
Top loading is the most efficient method of loading short verticals.
One of the best examples is shunt fed tower with a Yagi on top as the
top load. Another simple technique is a "T" top loaded wire. The
length from the feed point to one side of the "T" needs to be roughly
90% of a quarter wavelength, assuming a symmetrical "T". Impedance
matching can be done with an L-network or transmission line transformers.
Beware of PARASITIC effects from other towers/Yagi's. They CAN act as
a director or reflector to a separate vertical antenna, which is another
good
reason to use an existing tower as the 160M radiator by shunt feeding
or the simple reverse fed elevated GP concept described in JUNE 1994 QST.
BASE LOADED antennas are the LEAST efficient.
The GAP antennas use a transformed reactance to series load the antenna,
at the feedpoint,on the lowest frequency band which reduces efficiency on
that band.
All verticals perform best with 30 or more radials (up to 120 for
purists, 60 is GOOD).
de Tom N4KG
............................
On Thu, 26 Feb 1998 17:32:16 EST W2GR <W2GR@aol.com> writes:
>Hello all...Name Mike.
>Just curious if anyone might have any thoughts on any good 160
>verticals.
> I saw the Gladiador in NCJ ...curious abt it. A friend here has the
>Gap
>Voyager and said it isn't very good on 160. I'm relatively new to the
>hobby
>and just wet on 160 so any info will be greatly appreciated!
>Thanks in advance.
>73
>Mike W2GR
>
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